The present invention is directed to a write-protect clip for a floppy disc, and more particularly to a clip which can be permanently attached to a floppy disc and which can thereafter be removed to a position which exposes the floppy disc's write-protect notch or to a position which closes the notch.
A magnetic medium housed in a protective cover is commonly employed to store data and programs for personal computers. The magnetic medium, such as iron oxide, is deposited on both sides of a flexible, disc-shaped plastic sheet. Because of this the entire assembly is referred to as a "floppy disc" (although other designations such as "discette" or simply "disc" may also be used), even though the protective cover is usually square. The floppy disc is used by inserting it into a disc drive provided by the computer; the disc drive spins the plastic sheet bearing the magnetic medium and moves one or more magnetic read/write heads against the medium to record information on the medium or to receive previously recorded information from the medium. A disc drive is designed to cooperate with floppy discs having a particular size and protective cover configuration.
FIGS. 1 and 2 illustrate a floppy disc 20 which is widely used with personal computers, including the International Business Machines "PC" personal computer. The protective cover of floppy disc 20 is provided by a flexible plastic envelope 22 having four edges 24, 26, 28, and 30, a top side 32, and a bottom side 34. Edge 26 is provided with a rectangular write-protect notch 36 having ends 38 and 40. As will be seen from FIG. 2, the various edges are formed by border portions 42 which extend from top side 32 and which are folded around to bottom side 34, where the border portions 42 are bonded with bottom side 34 to seal envelope 22.
With continuing reference to FIGS. 1 and 2, floppy disc 20 also includes a circular plastic sheet 44 having magnetic medium deposited on its top and bottom sides. Sheet 44 is rotatable within envelope 22. Porous paper leaves 46 are adhesively attached to the inner walls of top side 32 and bottom side 34 and are impregnated with a lubricant to minimize friction with sheet 44 and to remove debris from the surface of sheet 44.
An adhesive paper label 48 is commonly applied to envelope 22 adjacent edge 24 to identify the contents of the disc. Sheet 44 has a central opening 50 which is bordered by an engagement region 52. Region 52 is engaged by the disc drive (not illustrated), through openings 54 in envelope 22, to spin sheet 44. Envelope 22 is also provided with elongated openings 56 which permit the magnetic heads (not illustrated) of the disc drive to move to various radial positions while in contact with sheet 44.
During use, edge 28 of floppy disc 20 is inserted into a slot (not illustrated) in the disc drive (not illustrated) and is locked into place by operating a lever (not illustrated) or similar mechanism. A sensor (not illustrated) within the disc drive is positioned to detect write-protect notch 36. The sensor may be mechanical, such as a microswitch, or electrical, such as an LED/photodiode combination. If notch 36 is open, as illustrated in FIG. 1, the operating system of the computer permits information to be both read from and recorded onto floppy disc 20. In some situations, however, it is desirable to protect floppy disc 20 from inadvertent changes or erasures. In such a situation one can write-protect the floppy disc 20 before inserting it into the drive by applying an adhesive strip (not illustrated) which covers notch 36. In such a situation notch 36 would not be detected by the sensor within the disc drive, whereupon the operating system would permit information to be read from floppy disc 20 but would prohibit changes from being made. That is, the floppy disc 20 would be write-protected.
The use of adhesive strips for write-protection has several disadvantages. Although floppy discs are typically sold with a supply of adhesive strips made specifically for write-protection, the user may have misplaced the strips when the need for them arises. This might tempt the user to try a substitute, with undesirable consequences if the substitute proves ineffective. Even if the user is careful to use only strips that are specifically intended for write-protection, the adhesive may eventually deteriorate due to the passage of time and the generation of heat within the disc drive. A detached strip could destroy both the disc drive and the floppy disc.